Q: Popping Sound with USB

Update-

Additional Testing Notes for USB Issue: This popping sound also occurs when playing the iTouch in Airport Mode, so not related to WiFi activity. The popping also occurs with all types of music source formats, whether original CD’s ripped in either iTunes Lossless or NERO Lossless (m4a) at above 400kbps, 256kbs MP3’s purchased from Amazon.com OR 256kbs M4A files from the iTunes Store. It is most noticeable with soft music or passages and with low level recordings that you must playback at a higher volume. This is all very interesting indeed.

Additional Notes:

Reading through other ‘posts’ reporting the same popping problems, it should be noted that this is a cross-platform problem, unrelated to either iMac or PC systems and solely with the iPod itself.

This makes it a product-wide problem for Apple. RECALL comes to mind... but most likely it is firmware/software fix.

‘We’ (the people), have done the R&D (freely) for you Apple (CEO, Tim Cook), we have identified the problem. Now it is time for you to step-up to the plate.

Final Notes:

Upon further review of other ‘posts’ reporting the same popping noise; it becomes obvious this problem is affecting both the Apple iPhone and iPod Touch. This USB playback popping noise problem is a Product-Wide problem across at least Two Product Lines and most likely affecting a huge number of units.

I report all of this in disbelief that a problem affecting so many units has continued for well over a year (when I've Identified the problem over a weekend). I imagine the iPhone’s antenna problem, how it must have cost Apple in sales and embarrassment… Please fix this problem, thanks.

Is this also a problem with the iPad? Please reply...

Conclusive Testing with Repeatable Results:

By preparing five WAVE files for testing (of 3mins each) as follows;  Silence (No Room Tone),  50Hz/-20dB single tone,  1kHz/-20dB single tone,  BrownNoise/-20dB,  and finally VioletNoise/-20dB (BrownNoise is simultaneous multi-low frequency tones and VioletNoise is simultaneous multi-high frequency tones).  Playback was made through iPod USB port of a new (out of box) Yamaha RX-V671 Receiver.

The Test Results:

With playback volume set at around -28dB (typical 100w amp),  the ‘Silence’ WAVE file produced no popping noise as was the same case with both 50Hz/-20dB single tone,  1kHz/-20dB single tone files.

However; when I played the BrownNoise/-20dB,  and  VioletNoise/-20dB WAVE files, the popping noise loudly occurred every time. This conclusively demonstrates that the iPod Touch/iPhone USB popping noise does exist and most likely related to how it processes that data thru a USB connection. The popping noise also had no relationship to the recorded amplitude and occured in a random nature each time.

Compared Product Testing:

Yes, this problem is ONLY with the APPLE products.

Just finished comparable tests on a Sony Walkman, using USB connection on both Home Theater System and Car Stereo.

The same tests (as above) using the same wave files on the same equipment, playback thru the Walkman was normal and did NOT exhibit any of the noises which plague the APPLE devices mentioned here.

Not good news for APPLE has we near the bigs sales season of the year, PLEASE Fix This Problem...

@ FockerRN and @ gh76

Thanks for the additional info.

@ FockerRN:

Are you saying that the popping noise is present when you use iTunes to playback (USB output) into an ext. DAC? I don’t see how this would be related as iTunes is reliant on the computer system. How does your DAC interface with the computer, it must have some type of USB interface (your USB-to-spdif)?  I would take a good look that the ‘drivers’ for that first. Either way, that issue would not change (or corrupted) the integrity of your music file library so no need to be alarmed there. Sounds like a driver issue.

That is a very bad practice; in doing that you risk the possibility of speaker damage or damage to either of the connecting devices (your iPod/iPhone). Making a 'LIVE' connection (connecting devices while they are Powered On) has never been advisable and the practice should be avoided with any and all electronic devices. Please read your device manual on how to properly Connect/Disconnect the device.